EP0123005B1 - Gripper for inserting a weft thread into a gripper weaving machine - Google Patents

Description

The invention relates to a gripper for the insertion of weft in a rapier weaving machine, with a clamping hook for the weft thread and an associated clamping tongue which can be displaced in the longitudinal direction of the gripper under spring action in a gripper frame, a flank of the clamping tongue head and a flank of the free end of the clamping hook cooperating therewith stand at an angle to the longitudinal direction of the gripper.

In a previous gripper of the type mentioned (DE-OS 3 033 201 = US-PS 4371 008), the clamping tongue is mounted in the gripper frame in such a way that when the clamp is formed by the clamping tongue head and the clamping hook, it is retracted only in the longitudinal direction of the gripper can be moved. This creates the disadvantage that a relatively large retraction movement of the clamping tongue is required until the weft thread clamped on the thread clamp is released. This applies in particular to thicker yarns or to yarns with an uneven or rough surface or to yarns with a varying thickness.

The invention has for its object to provide a gripper which is particularly improved in this regard.

The invention consists in that the other clamping hook flank - in comparison to the inclined position of the one clamping hook flank - is inclined in the opposite direction to the longitudinal direction of the gripper and forms a guide for the clamping tongue head during the opening movement of the clamping tongue.

This makes it possible to superpose a slight pivoting movement of the retracting movement of the thread clamp which occurs when the thread clamp is opened. As a result of the resulting movement of the clamping tongue, the tongue head is lifted from the clamping flank of the hook more quickly and in a shorter way.

This can prevent e.g. in the production of blended fabrics made from yarns of various qualities, e.g. Thickness or surface exist, after opening the clamp (at the end of the entry) there are weft ends of different lengths. Rather, it can be achieved that the weft thread ends are practically always of the same length regardless of the yarn quality, e.g. regardless of whether a thicker or thinner or a rougher or smoother thread is inserted. In addition, the time until the weft thread is completely released from the thread clamp or the retraction path of the clamping tongue can be kept shorter.

• Fig. 1 veranschaulicht einen Teil einer Vorderansicht einer Greifer-Webmaschine, an der die Erfindung ausgeführt ist,
• Fig. 2 erläutert schematisch die Schusseintragsteile, in grösserem Massstab,
• Fig. 3 ist eine Draufsicht auf einen Greifer der Webmaschine,
• Fig. 4 und 5 sind zwei Detaildarstellungen des Greifers in verschiedenen Positionen und in grösserem Massstab,
• Fig. 6 und 7 sind zwei den Fig. 4 und 5 entsprechende Darstellungen einer abgewandelten Bauart.

Further features emerge from the following description of exemplary embodiments in conjunction with the drawing and the claims.

• 1 illustrates part of a front view of a rapier weaving machine on which the invention is carried out,
• 2 schematically explains the weft insertion parts, on a larger scale,
• 3 is a plan view of a rapier of the weaving machine,
• 4 and 5 are two detailed representations of the gripper in different positions and on a larger scale,
• 6 and 7 are two representations of a modified type corresponding to FIGS. 4 and 5.

1, 2 contains a machine frame 1, a breast beam 11 and a central support 12. The weft insertion mechanism contains two drive wheels 4 arranged on both sides of the machine, each for a flexible entry belt 5. In FIG. 1 only the catch-side mechanism is shown . On the weft-side entry belt 5, a rapier 7 is attached to bring the weft thread 10 into the shed, on the catch-side entry belt 5 a taker gripper 6 is attached, through which the weft thread 10 is taken over in the middle of the shed by the taker gripper 6 and through the second half of the Shed is pulled.

The slave gripper 6 has a frame designated as a whole by 13, e.g. made of aluminum, which consists of a base plate 14 and two side walls 15, 16. In the frame 13, a clamping tongue 1 is slidably mounted (arrow 21). The clamping tongue 17 engages with a fork-shaped part 22 a pin 18 fastened on the base plate 14 and continues to the left in FIG. 3 into a pull arm 24. The clamping tongue 17 is thus pivotable about the pin 18 according to arrow 23.

At its right end in Fig. 3, the clamping tongue 17 has a larger one shown in Figs. 4, 5, attached to a connecting plate 50, e.g. made of hard metal clamping head 25, which - in the clamping position - is pressed under the action of a compression spring 27 together with the entire clamping tongue 17 into a hook 28 attached to the frame 13. The hook has a free end 29, the flank 31 of which is inclined relative to the longitudinal direction (longitudinal axis 32) of the gripper 6. With the hook flank 31, a correspondingly obliquely running flank 35 formed on the clamping head 25 cooperates.

On the clamping hook 28 there is also a flank 37, which is reversely oblique with respect to the axis 32 of the gripper 6 with respect to the axis 32 of the gripper 6 and with which a corresponding obliquely flank 38 of the clamping head 25 cooperates.

In the clamping position of the parts shown in FIG. 3, the thread 10 is clamped between the flanks 31, 35 and, according to FIG. 1, is pulled towards the catch side according to arrow 41 to the left. As soon as the gripper 6 runs into the guide 42, a stop 45 pivotally mounted on the base plate 14 at 44 is pivoted into the position 45a indicated by the dashed lines in FIG. As a result, a pull lamella 47 attached to the stop 45 at 46 is pulled to the left in FIG. 3.

Lamella 47 is attached to the pull arm 24 of the clamping tongue 17 eccentrically at 48 with respect to the pin 18 (lever arm 40). As a result, the clamping tongue 17 is shifted to the left and at the same time - due to the eccentric force effect by lamella 47 - is pivoted counterclockwise by a small amount. As a result, the clamping head 25 arrives in the opening position 25a indicated by dashed lines in FIG. 3, the flanks 37, 38 sliding on one another.

The inclination of these two flanks enables the clamping tongue 17 to receive a rotary movement about the pin 18 during its left-hand movement, as a result of which the clamping flanks 31, 35 reach the opening position more quickly and the thread 10 is released more quickly, even if it is a thicker weft yarn .

On the side wall 15 there is also a wedge 51 with an oblique flank 52 which cooperates with a corresponding oblique flank 53 formed on the clamping tongue 17. During the left shift of the clamping tongue 17, the pivoting movement about the pin 18 is supported by the wedge 51. Wedge 51 also forms a counterpart to the flank 37 of the hook 29, which prevents vibrations of the clamping tongue 17 during its left movement and the superposed pivoting by 18.

6, 7, a pin 61 is fastened on the base plate 14 and cooperates with a curved slot 62 of the clamping tongue 17.

When the clamping tongue 17 is moved downward from the clamping position shown in FIG. 6 into the open position shown in FIG. 7 according to arrow 21, the upper end of the slot 62 passes over the pin 61, whereby the clamping tongue 17 pivots during its downward movement Receives counter-clockwise. As a result, the clamping head 25 reaches the opening position 25a shown in FIG. 7, the flanks 37, 38 sliding on one another.

In another embodiment, the wedge 51 is omitted, since the pulling force directed towards the left in FIG. 3 and acting on the lamella 47 at 48 with respect to the pin 18 is arranged eccentrically (lever arm 40), nevertheless, arises in FIG Torque on the clamping tongue 17 directed counterclockwise by 18. As a result, the clamping head 25 is also moved into the open position 25a while the two flanks 37, 38 slide onto one another and thus in the shortest possible way and in the shortest possible time.

However, a design is also possible in which the tension plate 47 engages in the clamping tongue axis 32 and thus centrally to the pin 18. Then the wedge 51 is required, by which it is ensured that the clamping tongue, in addition to its longitudinal movement, is pivoted about the pin 18 according to arrow 23. Instead of wedge 51, e.g. a magnet attached to the side wall 16 can also be used, by means of which the tongue 17 is pulled upwards during the movement to the left in FIG. 3 and is thus pivoted.

The tongue 17 can then optionally also be made of an elastic material, e.g. Plastic. The head 25 can then be held under a bias of the tongue 17 in the clamping position shown in FIG. 4. When the tongue 17 is retracted to open the clamp, the flanks 37, 38 slide on one another under the pretension, so that at least the clamping head 25 of the tongue 17, apart from the longitudinal movement, experiences a pivoting movement with respect to the bearing point 18 (transverse movement to the longitudinal axis 32).

It is crucial that, in any case, during the opening of the clamp formed by the parts 29, 25, in addition to the sliding movement of the tongue 17, a pivoting movement about the pin 18 is superposed.

Correspondingly, the bringer gripper 24 can also be equipped with clamping parts which have inclined flanks to produce a swiveling movement superposed on the translatory pulling movement.

Claims (5)

1. A gripper for weft picking in a gripper weaving machine, the gripper comprising: a clamping hook (28) for the weft yarn (10); and an associated clamping tongue (17) movable by spring force (27) lengthwise (32) of the gripper in a gripper frame (13), one flank (35) of the clamping tongue head (25) and a flank (31) co-operating therewith of the free end (29) of the clamping hook (28) being at an inclination to gripper length (32), characterised in that the other clamping hook flank (37) is, in comparison with the inclination of the first clamping hook flank (31), at an inclination in the opposite direction to gripper length (32) and forms a guide for the clamping tongue head (25) during the opening movement of the clamping tongue (17).

2. A gripper according to claim 1, characterised in that the clamping tongue (17), in addition to being movable lengthwise, is mounted for pivoting in the gripper frame (13).

3. A gripper according to claim 1 and 2, characterised by an inclined wedge (51) which is disposed on the gripper frame (13) and which during the opening movement of the clamping tongue (17) acts on the gripper pivot arm carrying the clamping tongue head (25).

4. A gripper according to claim 1 and 2, characterised in that one or the other of the clamping tongue (17) and gripper frame (13) has a pin (61) and the other one of the clamping tongue (17) and gripper frame (13) is formed with an inclined slot (62) which engages over the pin (61 to produce a pivoting of the clamping tongue (17) operative in the opening of the clamp (25, 28).

5. A gripper according to any of claims 2-4, characterised in that a return element (47) actuating the clamping tongue (17) engages eccentrically, as referred to the clamping tongue fulcrum (18), with a withdrawal arm (24) of the clamping tongue (17).

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